Primox® is the oxygenation of sewage within the sewage system itself. The oxygen is usually injected into rising mains. Primox is an effective means of preventing septicity as well as an economic pre-treatment of sewage before it arrives at a works.
When starved of dissolved oxygen, particularly in longer mains or where long retention takes place, bacterial action can strip out the combined oxygen from the sulphates and nitrates in the sewage, producing sulphides and other harmful compounds. The result is septicity, foul odours and sewage with poor settling characteristics.
Primox® was developed by BOC to overcome this. Using very simple equipment, oxygen is injected at the base of the rising main in quantities sufficient to maintain aerobic conditions through its entire length.
The normal approach is to ensure that the facultative bacteria are always supplied with sufficient dissolved oxygen for aerobic respiration during the retention period in the main - and hence anaerobic conditions and consequent generation of sulphides do not occur.
Using pure oxygen it is possible to store substantial quantities of oxygen in the dissolved state. This has the added benefit of having some biological treatment of the waste (reduction of organic compounds to less harmful products) and controlling odours further down a reticulation system. Whereas other chemical-in-main treatments will control sulphides, they provide no additional benefit to the customer.
Using pure oxygen as means of sulphide generation prevention is a technology that has proven to be beneficial.
BOC has been designing and installing oxygen-based systems around the world for over 25 years.
There are many methods of dissolving pure oxygen into wastewater. BOC has the experience of over 100 installations from which to develop the most efficient gas injection method.